Study On The Effect Of High Viscosity Crude Oil On The Separation Performance Of Downhole Cyclone

At present,with the application of steam injection thermal recovery and viscosity reduction by oil blending in heavy oil reservoir,heavy oil production is faced with the continuous increase of moisture content.The viscosity change of heavy oil will directly affect the fluid flow state and separation performance of downhole cyclone.In order to solve this problem,this paper studies the influence of high viscosity crude oil on the separation performance of downhole cyclone.Firstly,based on Euler's two-phase flow theory,the RSM model is selected to simulate the flow field of the downhole cyclone,and the numerical model of liquid-liquid two-phase turbulence in the downhole cyclone separator is established.The established model calculation method was applied to establish the same model as the experiment,oil and water were used as the flow medium,and FLUENT software was used to conduct numerical simulation calculation for the cyclone separator.The numerical simulation results are in good agreement with the experimental results,which verifies the correctness of the numerical solution and the selection of turbulence model,and proves that the numerical simulation model established in this paper can be used to study the downhole cyclone separator.Secondly,according to the characteristics of oil reservoirs,the diversion ratio is determined by numerical simulation.On the premise of the diversion ratio,the effects of crude oil viscosity change on the velocity field,pressure field,turbulence intensity,volume fraction of oil phase,migration characteristics of oil-water two-phase media and separation performance of the cyclone separator were investigated.The flow-efficiency numerical analysis of cyclone separator under different viscosity of crude oil is carried out,and the law of separation efficiency with flow rate is investigated,which provides a reference for reasonable adjustment of flow rate to obtain better separation effect.Then,the effects of moisture content change on the velocity field,pressure field,turbulence intensity,oil phase volume fraction,oil and water two-phase medium migration characteristics and separation performance were investigated.At the same time,the comprehensive effects of moisture content and crude oil viscosity on the separation efficiency of hydrocyclone are analyzed.Furthermore,the numerical analysis of downhole cyclone separator is carried out by using orthogonal test method.Within the scope of study,the primary and secondary factors affecting the separation performance of cyclone are obtainedand the relationship between primary and secondary factors is obtained.Finally,according to the actual production conditions and the physical properties of the produced fluid,the typical double-cone and single-cone cyclone separator models were numerically simulated.The separation efficiency and pressure loss under different moisture content and crude oil viscosity were compared and analyzed,and the applicability of the swirling fluid structure to the actual conditions of oil-water separation of high viscosity liquid was explored.The work of this paper can provide reference for the application of injection-production technology in the same well in the condition of heavy oil with high moisture content.